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Smart Agriculture ›› 2020, Vol. 2 ›› Issue (4): 124-136.doi: 10.12133/j.smartag.2020.2.4.202003-SA005

• 专刊--农业机器人与智能装备 • 上一篇    下一篇

不同飞行参数下八旋翼植保无人机下洗气流场对雾滴沉积分布特性的影响

王昌陵1,2(), 何雄奎1,3(), BONDSJane4, 齐鹏1,3, 杨苡5, 高万林2()   

  1. 1.中国农业大学 药械与施药技术研究中心,北京 100193
    2.中国农业大学 信息与电气工程学院,北京 100094
    3.中国农业大学 理学院,北京 100193
    4.邦德斯咨询有限公司,巴拿马城 32408,美国
    5.北方天途航空技术发展(北京)有限公司,北京 102202
  • 收稿日期:2020-03-10 修回日期:2020-04-20 出版日期:2020-12-30 发布日期:2021-02-05
  • 基金资助:
    中国博士后科学基金资助项目(2019M650907);中国农业大学基本科研业务费专项资金项目(2019TC230);国家自然科学基金资助项目(31761133019)
  • 作者简介:王昌陵(1991-),男,博士,博士后,研究方向为低空低量施药技术。E-mail:WCL1991@cau.edu.cn
  • 通讯作者: 何雄奎,高万林 E-mail:WCL1991@cau.edu.cn;xiongkui@ cau.edu.cn;gaowlin@cau.edu.cn

Effect of Downwash Airflow Field of 8-rotor Unmanned Aerial Vehicle on Spray Deposition Distribution Characteristics under Different Flight Parameters

WANG Changling1,2(), HE Xiongkui1,3(), BONDS Jane4, QI Peng1,3, YANG Yi5, GAO Wanlin2()   

  1. 1.Centre for Chemicals Application Technology, China Agricultural University, Beijing 100193, China
    2.College of Information and Electrical Engineering, China Agricultural University, Beijing 100094, China
    3.College of Science, China Agricultural University, Beijing 100193, China
    4.Bonds Consulting Group LLC, Panama City 32408, USA
    5.Beijing TT Aviation Technology Co. Ltd. , Beijing 102202, China
  • Received:2020-03-10 Revised:2020-04-20 Online:2020-12-30 Published:2021-02-05
  • corresponding author: Xiongkui HE,Wanlin GAO E-mail:WCL1991@cau.edu.cn;xiongkui@ cau.edu.cn;gaowlin@cau.edu.cn

摘要:

近年来,应用植保无人机防治农业有害生物已成为中国植保机械发展的一大新亮点。无人机旋翼提供飞行升力的同时具有下洗气流场,低空低量施药作业雾滴沉积分布质量优劣与旋翼下洗气流场的作用密不可分。为探究植保无人机旋翼下洗气流场对喷雾效果的影响,本研究以当前植保无人机主流机型——“X型”布局八旋翼无人机为研究对象,采用实际作业测试方式,利用微气象测量系统测定无人机飞行状态下旋翼下方不同水平位置下洗气流场风速,同时采用诱惑红示踪剂水溶液代替农药喷雾获取喷雾沉积分布情况,重点对下洗气流场分布实测结果进行可视化分析,包括不同飞行高度、不同速度下旋翼下洗气流场分布特性与雾滴沉积分布特性以及二者的相互关系。测试结果显示:八旋翼植保无人机飞行过程中随着飞行速度加快(1.0~6.0 m/s)和飞行高度升高(1~2 m),冠层位置XYZ三向下洗气流场总体表现为气流强度由强到弱、分布状态由集中到分散的变化趋势;X方向气流来源于下洗气流与外界空气相互作用产生的卷扬气流,对喷施雾滴的作用为逆飞行方向;Y方向为下洗卷扬气流以及地面效应共同作用的结果,对雾滴的作用为垂直于航线朝向两侧;Z方向为下洗气流竖直向下方向分量,对雾滴下降沉积具有直接促进作用;飞行速度与下洗气流场范围内风速峰值(P<0.05,r=-0.836)和有效喷幅内平均沉积量(P<0.05,r=-0.833)均表现出显著负相关;在飞行速度为1.0 m/s和3.0 m/s时,雾滴沉积量与下洗气流场风速均呈现极显著正相关关系(P<0.01,r>0),即垂直地面方向的下洗气流场越强,有效喷幅内沉积的雾滴越多;速度加快至6.0 m/s,风速显著降低,气流场对雾滴沉积的促进作用逐步消失(P>0.05)。因此,植保无人机作业时飞行速度不应设置超过6.0 m/s,避免因下洗气流场作用减弱而导致雾滴损失。本研究结果可为改善低空低量施药作业质量和无人机田间作业规范的制定提供技术参考和支撑。

关键词: 植保无人机, 雾滴, 八旋翼, 下洗气流场, 沉积分布

Abstract:

Pesticide application using UAV sprayer has become a new highlight in the development of agricultural machinery and plant protection in China. Spray droplets from UAV could reach the crop canopy and deposit on the control target surface under the assistance of rotor's downwash airflow after atomization, including a secondary atomization effect of airflow on the droplets, so the spray performance of aerial pesticide application is inseparable from the effect of the rotor's downwash airflow field. In order to explore the effect of downwash airflow field on UAV's spray deposition characteristics, taking the main model of eight-rotor UAV with "X-type" as the research object and designing the actual measuring test, a multi-channel micro-meteorology measurement system(MMMS) was used to determine the downwash airflow speed at different horizontal positions, and meanwhile the tracer Allura Red solution was applied instead of chemicals to obtain the distribution characteristics of spray deposition. The visual analysis of the measured results of the downwash airflow field distribution was focused, and then the distribution characteristics of both the downwash airflow field and the droplet deposition at a certain flight height and speed, and the correlation relationship between them were analyzed. During the flight operation of the 8-rotor UAV, as the flight speed increased from 1.0 to 6.0 m/s and the flight height increased from 1 to 2 m, the intensity of the downwash airflow field in directions of X, Y, and Z generally changed from strong to weak, and the distribution state changed from concentration to dispersion; the X direction airflow was the vortex generated by the interaction between the downwash airflow and the outside air and its effect on droplets was reversed flight direction; the airflow in Y direction was to the both sides from flight path, caused by the combination of downwash airflow and ground effect; the airflow in Z direction, the vertical downward component of the downwash airflow, had a direct promotion effect on spray deposition. Significant negative correlations were shown between both the flying speed and the peak value in the range of the downwash airflow field (P <0.05, r = -0.836), and the flying speed and the average deposition within the effective spray swath(P <0.05, r = -0.833). When the flight speed was 1.0 and 3.0 m/s, the droplet deposition showed a very significant positive correlation with downwash airflow speed(P <0.01, r> 0), that was, the stronger the downwash airflow field in the vertical ground direction, the more droplets deposited in the effective spray swath. When the flight speed increased to 6.0 m/s, the wind speed was significantly reduced, and the promotion effect of the downwash airflow field on the droplet deposition disappeared(P> 0.05). The operation speed of UAV should not be set faster than 6.0 m/s to avoid the chemicals loss caused by the weakened effect of the downwash airflow field. The findings of this study are expected to provide theoretical basis and data support for improving the quality of low-altitude and low-volume application operations and the formulation of UAV field operations specifications.

Key words: unmanned aerial vehicle, droplet, 8-rotor, downwash airflow field, deposition distribution

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